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<h1 class="title">waveform.h Example File</h1>
<span class="subtitle">multimedia/spectrum/app/waveform.h</span>
<!-- $$$multimedia/spectrum/app/waveform.h-description -->
<div class="descr"> <a name="details"></a>
<pre class="cpp">
<span class="comment">/****************************************************************************
**
** Copyright (C) 2017 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the examples of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:BSD$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see https://www.qt.io/terms-conditions. For further
** information use the contact form at https://www.qt.io/contact-us.
**
** BSD License Usage
** Alternatively, you may use this file under the terms of the BSD license
** as follows:
**
** "Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions are
** met:
** * Redistributions of source code must retain the above copyright
** notice, this list of conditions and the following disclaimer.
** * Redistributions in binary form must reproduce the above copyright
** notice, this list of conditions and the following disclaimer in
** the documentation and/or other materials provided with the
** distribution.
** * Neither the name of The Qt Company Ltd nor the names of its
** contributors may be used to endorse or promote products derived
** from this software without specific prior written permission.
**
**
** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
**
** $QT_END_LICENSE$
**
****************************************************************************/</span>
<span class="preprocessor">#ifndef WAVEFORM_H</span>
<span class="preprocessor">#define WAVEFORM_H</span>
<span class="preprocessor">#include <QAudioFormat></span>
<span class="preprocessor">#include <QPixmap></span>
<span class="preprocessor">#include <QScopedPointer></span>
<span class="preprocessor">#include <QWidget></span>
<span class="comment">/**
* Widget which displays a section of the audio waveform.
*
* The waveform is rendered on a set of QPixmaps which form a group of tiles
* whose extent covers the widget. As the audio position is updated, these
* tiles are scrolled from left to right; when the left-most tile scrolls
* outside the widget, it is moved to the right end of the tile array and
* painted with the next section of the waveform.
*/</span>
<span class="keyword">class</span> Waveform : <span class="keyword">public</span> <span class="type">QWidget</span>
{
Q_OBJECT
<span class="keyword">public</span>:
<span class="keyword">explicit</span> Waveform(<span class="type">QWidget</span> <span class="operator">*</span>parent <span class="operator">=</span> <span class="number">0</span>);
<span class="operator">~</span>Waveform();
<span class="comment">// QWidget</span>
<span class="type">void</span> paintEvent(<span class="type">QPaintEvent</span> <span class="operator">*</span>event) override;
<span class="type">void</span> resizeEvent(<span class="type">QResizeEvent</span> <span class="operator">*</span>event) override;
<span class="type">void</span> initialize(<span class="keyword">const</span> <span class="type"><a href="qaudioformat.html">QAudioFormat</a></span> <span class="operator">&</span>format<span class="operator">,</span> <span class="type">qint64</span> audioBufferSize<span class="operator">,</span> <span class="type">qint64</span> windowDurationUs);
<span class="type">void</span> reset();
<span class="type">void</span> setAutoUpdatePosition(bool enabled);
<span class="keyword">public</span> <span class="keyword">slots</span>:
<span class="type">void</span> bufferChanged(<span class="type">qint64</span> position<span class="operator">,</span> <span class="type">qint64</span> length<span class="operator">,</span> <span class="keyword">const</span> <span class="type">QByteArray</span> <span class="operator">&</span>buffer);
<span class="type">void</span> audioPositionChanged(<span class="type">qint64</span> position);
<span class="keyword">private</span>:
<span class="keyword">static</span> <span class="keyword">const</span> <span class="type">int</span> NullIndex <span class="operator">=</span> <span class="operator">-</span><span class="number">1</span>;
<span class="type">void</span> deletePixmaps();
<span class="comment">/*
* (Re)create all pixmaps, repaint and update the display.
* Triggers an update();
*/</span>
<span class="type">void</span> createPixmaps(<span class="keyword">const</span> <span class="type">QSize</span> <span class="operator">&</span>newSize);
<span class="comment">/*
* Update window position.
* Triggers an update().
*/</span>
<span class="type">void</span> setWindowPosition(<span class="type">qint64</span> position);
<span class="comment">/*
* Base position of tile
*/</span>
<span class="type">qint64</span> tilePosition(<span class="type">int</span> index) <span class="keyword">const</span>;
<span class="comment">/*
* Structure which identifies a point within a given
* tile.
*/</span>
<span class="keyword">struct</span> TilePoint
{
TilePoint(<span class="type">int</span> idx <span class="operator">=</span> <span class="number">0</span><span class="operator">,</span> <span class="type">qint64</span> pos <span class="operator">=</span> <span class="number">0</span><span class="operator">,</span> <span class="type">qint64</span> pix <span class="operator">=</span> <span class="number">0</span>)
: index(idx)<span class="operator">,</span> positionOffset(pos)<span class="operator">,</span> pixelOffset(pix)
{ }
<span class="comment">// Index of tile</span>
<span class="type">int</span> index;
<span class="comment">// Number of bytes from start of tile</span>
<span class="type">qint64</span> positionOffset;
<span class="comment">// Number of pixels from left of corresponding pixmap</span>
<span class="type">int</span> pixelOffset;
};
<span class="comment">/*
* Convert position in m_buffer into a tile index and an offset in pixels
* into the corresponding pixmap.
*
* \param position Offset into m_buffer, in bytes
* If position is outside the tile array, index is NullIndex and
* offset is zero.
*/</span>
TilePoint tilePoint(<span class="type">qint64</span> position) <span class="keyword">const</span>;
<span class="comment">/*
* Convert offset in bytes into a tile into an offset in pixels
* within that tile.
*/</span>
<span class="type">int</span> tilePixelOffset(<span class="type">qint64</span> positionOffset) <span class="keyword">const</span>;
<span class="comment">/*
* Convert offset in bytes into the window into an offset in pixels
* within the widget rect().
*/</span>
<span class="type">int</span> windowPixelOffset(<span class="type">qint64</span> positionOffset) <span class="keyword">const</span>;
<span class="comment">/*
* Paint all tiles which can be painted.
* \return true iff update() was called
*/</span>
bool paintTiles();
<span class="comment">/*
* Paint the specified tile
*
* \pre Sufficient data is available to completely paint the tile, i.e.
* m_dataLength is greater than the upper bound of the tile.
*/</span>
<span class="type">void</span> paintTile(<span class="type">int</span> index);
<span class="comment">/*
* Move the first n tiles to the end of the array, and mark them as not
* painted.
*/</span>
<span class="type">void</span> shuffleTiles(<span class="type">int</span> n);
<span class="comment">/*
* Reset tile array
*/</span>
<span class="type">void</span> resetTiles(<span class="type">qint64</span> newStartPos);
<span class="keyword">private</span>:
<span class="type">qint64</span> m_bufferPosition;
<span class="type">qint64</span> m_bufferLength;
<span class="type">QByteArray</span> m_buffer;
<span class="type">qint64</span> m_audioPosition;
<span class="type"><a href="qaudioformat.html">QAudioFormat</a></span> m_format;
bool m_active;
<span class="type">QSize</span> m_pixmapSize;
<span class="type">QVector</span><span class="operator"><</span><span class="type">QPixmap</span><span class="operator">*</span><span class="operator">></span> m_pixmaps;
<span class="keyword">struct</span> Tile {
<span class="comment">// Pointer into parent m_pixmaps array</span>
<span class="type">QPixmap</span><span class="operator">*</span> pixmap;
<span class="comment">// Flag indicating whether this tile has been painted</span>
bool painted;
};
<span class="type">QVector</span><span class="operator"><</span>Tile<span class="operator">></span> m_tiles;
<span class="comment">// Length of audio data in bytes depicted by each tile</span>
<span class="type">qint64</span> m_tileLength;
<span class="comment">// Position in bytes of the first tile, relative to m_buffer</span>
<span class="type">qint64</span> m_tileArrayStart;
<span class="type">qint64</span> m_windowPosition;
<span class="type">qint64</span> m_windowLength;
};
<span class="preprocessor">#endif // WAVEFORM_H</span>
</pre>
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<!-- @@@multimedia/spectrum/app/waveform.h -->
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